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To: python-list@python.org
From: Peter Otten <__peter__@web.de>
Subject: Re: Please code review.
Date: Tue, 02 Aug 2011 14:27:03 +0200
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Karim wrote:

> I need a generator to create the cellname in a excell (using pyuno)
> document to assign value to the correct cell. 

Isn't there a way to use a (row, column) tuple directly? If so I'd prefer 
that. Also, there used to be an alternative format to address a spreadsheet 
cell with something like "R1C2".

> The following code does this but do you have some
> optimizations
> on it, for instance to get the alphabetic chars instead of hard-coding it.
> 
> Cheers
> karim
> 
> Python 2.7.1+ (r271:86832, Apr 11 2011, 18:13:53)
> [GCC 4.5.2] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>  >>> def _xrange_cellnames(rows, cols):
> ...     """Internal iterator function to compute excell table
> cellnames."""
> ...     cellnames = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
> ...     for row in xrange(1, rows+1):
> ...         for char in cellnames.replace('', ' ').split()[:cols]:

That is interesting ;) But for maximum clarity use

for char in cellnames[:cols]:

instead.

> ...             yield char + str(row)
> ...
>  >>> list( _xrange_cellnames(rows=3,cols=4))
> ['A1', 'B1', 'C1', 'D1', 'A2', 'B2', 'C2', 'D2', 'A3', 'B3', 'C3', 'D3']

Here's my (untested) attempt to handle columns beyond "Z":

from itertools import chain, count, imap, islice, product
from string import ascii_uppercase

def columnnames():
    alpha = (ascii_uppercase,)
    return imap("".join, chain.from_iterable(product(*alpha*i) for i in 
count(1)))

def cellnames(columns, rows):
    for row in xrange(1, rows+1):
        for column in islice(columnnames(), columns):
            yield column + str(row)


if __name__ == "__main__":
    import sys
    print list(cellnames(*map(int, sys.argv[1:])))

I think the subject has come up before; goo^h^h^h the search engine of your 
choice is your friend.